The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Electro migration tests are used as a backend test in fabrication plants to determine the reliability of metal interconnects. Commonly, electro migration is performed at a package level (EM), or electro migration is performed at the wafer level (WLEM).
In either case, multiple test sites are required for testing to ensure sufficient time to fail data can be gathered to access the reliability of the process. The necessity to use multiple test sites increases the number of hours of testing and therefore the expense of testing. Reducing the number of sites needed to obtain similar results would result in significant cost and time savings.
During electro migration testing, the resistance of the structure under test is monitored while the structure is stressed. Stressing of the structure involves the use of a constant temperature and forcing a constant current through the structure.